This invention generally relates to intravascular catheters which are adapted for right coronary artery use and, more specifically, to guiding catheters for guiding dilatation catheters and the like into a patient's right coronary artery in procedures such as percutaneous transluminal coronary angioplasty (PTCA).
In the classic PTCA procedure, a guiding catheter having a preformed distal tip is percutaneously introduced into the cardiovascular system of a patient and advanced therein until the distal tip thereof is in the ostium of the desired coronary artery. A guidewire and a dilatation catheter having a balloon on the distal end thereof are introduced into and advanced through the guiding catheter to the distal tip thereof, with the guidewire slidably disposed within an inner lumen of the dilatation catheter. The guidewire is first advanced out the distal tip of the guiding catheter into the patient's coronary vasculature until the distal end of the guidewire crosses the lesion to be dilated, then the dilation catheter is advanced over the previously advanced guidewire until the dilatation balloon is properly positioned across the lesion. Once properly positioned, the balloon is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., generally 4-12 atmospheres) to dilate the lumen of the diseased artery. The balloon is then deflated so that the dilatation catheter can be removed and blood flow resumed through the dilated artery.
Further details of guiding catheters, dilatation catheters, guidewires, and the like for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,468,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,582,185 (Samson); U.S. Pat. No. 4,616,652 (Simpson); and U.S. Pat. No. 4,638,805 (Powell) which are hereby incorporated herein in their entirety by reference thereto.
Typically, a right Judkins guiding catheter is employed when performing a PTCA in a right coronary artery. A guiding catheter with an Amplatz curve can be used, but such a catheter is used with less frequency because it can cause injury to the coronary artery ostium if it is removed too quickly. The right Judkins catheter generally has three curves in the distal end, primary curve at the very distal tip, a much larger radiused secondary curve about 4-6 cm proximal from the primary curve and a tertiary curve proximal to the secondary curve having a much larger radius of curvature than the secondary curve. For a detailed description of the right Judkins guiding catheter, reference is made to RADIOLOGICAL CLINICS OF NORTH AMERICA Vol. VI, No. 3 December 1968 which is incorporated herein by reference.
However, the distal tip of the right Judkins catheter can be difficult to place within the ostium of the right coronary artery and once properly placed in the ostium thereof the distal tip can be easily displaced therefrom during angioplasty and other coronary vascular procedures. For example, the distal tip can back out of the ostium and interfere with proper placement of dilatation catheters into the coronary anatomy.
Many guiding catheters used in angioplasty procedures have perfusion ports a short distance proximal to the distal end so that, when the distal tip is seated within the coronary ostium, blood within the aorta will perfuse through the ports into the inner lumen of the guiding catheter and out the axial opening in the distal tip. However, when radiopaque dye is injected through the guiding catheter from the proximal end thereof, much of the dye is ejected out through the perfusion ports into the aorta. Because of the loss of dye into the aorta, insufficient dye will be introduced into the coronary arteries through the distal tip of the guiding catheter which makes fluoroscopic observation of the catheter very difficult.
What has been needed and heretofore unavailable is a guiding catheter which is easily positioned within the patient's right coronary artery and which provides sufficient distal push to the distal end of the catheter to ensure its placement within the ostium during vascular procedures. Additionally, there is also a need for a guiding catheter having perfusion ports in the distal end which minimize the ejection of radiopaque dye into the aorta without loss of blood perfusion characteristics. The catheter designs of the present invention satisfy these needs.